Sealing device for cylinder bearings

ABSTRACT

The invention relates to a sealing device for cylinder bearings. An annular projection which is connected to the cylinder neck ( 2 ) in a rotationally fixed manner carries an annular sealing surface which interacts with an elastic, stationary sealing element ( 23, 24 ), a sealing labyrinth consisting of stationary parts and parts which are connected to the cylinder ( 1 ) being placed upstream from the sealing element ( 13 ) towards the cylinder barrel. The aim of the invention is to develop one such sealing device in such a way that good sealing action can be achieved using simple and cost-effective sealing elements, and the durability of the seal increased in relation to that created by known sealing devices in such a way that the entire sealing device is cheaper. To this end, the labyrinth consists of a ring ( 7 ) having an essentially C-shaped cross-section and being linked to the front side of the cylinder in a sealed manner, a stationary, annular closing cover ( 9 ) plunging into the C-shaped opening of said ring; a drainage groove ( 30 ) which is open towards the outside is provided on the outside of the annular closing cover; the labyrinth opening ( 14 ) is situated at a distance from the bottom of the drainage groove; and the annular closing cover comprises an extension ( 10 ), the outer side of said extension creating a-deviation in the path of the labyrinth, and the inner side of said extension comprising a holding element for the stationary sealing element.

[0001] The invention relates to a seal assembly for a roll bearingwherein an annular element fixed rotationally to the roll stub forms anannular seal face for an elastic stationary seal element, a labyrinthseal formed of stationary parts and parts on the roll being providedbetween the seal element and the roll body.

[0002] Such seal assemblies have long been used in oil-film bearings. Asa rule expensive seals are used which on the one hand prevent oil fromgetting from the oil-film bearing to the roll body and on the other handprevent particle-carrying coolant and lubricant from getting from theroll body into the oil-film bearing.

[0003] In addition to bearings provided with stationary seals bearingsare known where the seals are connected to the roll stub, that is theseal elements rotate and engage stationary seal surfaces. Even hereexpensive seal rings are used in order to provide the necessary sealingbetween the roll and the bearing.

[0004] It is an object of the invention to provide a seal assembly ofthis type that, in spite of simple and inexpensive seal elements, sealseffectively and where by the service life of the seal assembly relativeto the known seal assemblies is larger so that the seal assembly worksout to be more cost effective.

[0005] In order to achieve this object, the invention proposes that thelabyrinth be formed by a C-section ring sealingly fixed on an end of theroll and forming a C-shaped cavity receiving a stationary annular coverpart, that the annular cover part form an outwardly open external draincompartment, that the labyrinth gap be remote from a floor of the draincompartment, and that the annular cover part have an extension whoseouter side forms part of the labyrinth path and whose inside carries thestationary seals.

[0006] The labyrinth seal thus seals the roll-side of the bearing whilethe seal elements only seal the bearing side. Thus expensive sealelements that are normally used in both locations, are not necessary.

[0007] Most of the coolant and lubricant running off the roll surfacearrives at one side of a wedge-shaped diverter. Rotation of thewedge-shaped diverter drives the coolant and lubricant to its edge wherethe centrifugal force is at its greatest. Most of the coolant andlubricant is spun off here. The remaining coolant and lubricant movesagainst the centrifugal force toward the bearing. The centrifugal forceis however effective such that the coolant and lubricant on the outsideof the diverter is moved to the point of the diverter. The greatestportion of the coolant and lubricant not spun off the diverter gets intothe drain compartment and is fed thence to a receptacle.

[0008] Even so, lubricant and coolant can get into the labyrinth seal.As soon as drops contact the rotating parts of the labyrinth seal, theyare moved outward by centrifugal force. Only those drops that collect onthe stationary part of the labyrinth seal drip in a first region of thelabyrinth seal onto the leg of the C-section ring whence the coolant andlubricant are moved outward by centrifugal force.

[0009] Any remaining lubricant and coolant in the labyrinth on the innerface of the inner leg of the C-section ring is trapped by a groove andthence moved to the catchment groove(s). The catchment grooves collectthe droplets which flow to the lowest part of the catchment groove wherethe coolant and lubricants flow out through the outlet passage from thelabyrinth to the drain compartment.

[0010] The labyrinth forms with the extension an additional bend. Herethe rotating elements of the labyrinth are shaped such that the coolantand lubricant are driven by centrifugal force into the outlet passages.

[0011] At the end of the labyrinth path the extension has an add-onpiece that greatly restricts the labyrinth path so that at this end thelast bits of coolant and lubricant are trapped and moved off to thedrain compartment.

[0012] It has proven advantageous to use as seal element a radial glandseal ring whose seal lip has at least one annular spring pressing theseal lip against the seal face. Such glands are standard seals inmachines and are not expensive or difficult to manufacture. Theadvantage is that when two identical seal rings are provided together itis possible to surely prevent oil from getting from the bearing regioninto the labyrinth region.

[0013] It is preferable when an input/output passage is provided betweenthe two glands to lubricate the second seal lip and to carry off excessoil.

[0014] The invention is described more closely with reference to adrawing.

[0015] Therein:

[0016]FIG. 1 is a view of a roll with an oil-film bearing and

[0017]FIG. 2 is a detail of the seal.

[0018]FIG. 1 shows a roll 1 having a roll stub 2. The roll stub 2 isfitted with a bearing sleeve 3 with an extension 4. In addition a partof a support part 5 as well as the bearing sleeve 6 are shown. AC-section ring 7 is fixed by screws 8 on the end of the roll 1. TheC-shaped cavity of the C-section ring 7 receives an annular seal part 9that is fixed on the support part 5. The annular seal part 8 forms anannular outwardly open drain compartment 30. The annular seal part 9 isjuxtaposed with an extension 10.

[0019]FIG. 2 shows how an outer leg 11 of the C-section ring 7 forms anouter wedge-shaped diverter 12. The wedge-shaped diverter 12 ensuresthat coolant and lubricant flowing from the roll 1 collects at its sharpedge where the centrifugal force is greatest and is thrown off from thisedge. In addition the coolant and lubricant collect generally in thedrain compartment 30 and flow out from it so it cannot get into alabyrinth 13.

[0020] Small amounts of coolant and lubricant can nonetheless getthrough a gap 14 into the labyrinth 13. If these droplets come intocontact with the rotating C-section ring 7, they will be taken up andtransported by centrifugal force to the outer leg 11 and thence thedroplets leave the labyrinth through the gap 14.

[0021] If droplets in the labyrinth 13 land on the annular seal part 9,they will move outward on this part and, depending on their location,will either end up on the outer leg 11 or an inner leg 15 of theC-section ring 7. Thence the droplets are driven by centrifugal forcethrough the gap 14.

[0022] Remnants of coolant and lubricant that go deeper into thelabyrinth 13 are caught by the inner leg 15 which has a groove 16. Thedroplets collect on the flanks of the groove or in the groove and arecentrifugally driven into catchment grooves 17 and 18. The catchmentgrooves 17 and 18 are formed in the annular seal part 9. The lower partof FIG. 2 shows outlet passages 19 and 20 formed in the catchmentgrooves 17 and 18 and from which the coolant and lubricant collecting inthe grooves 17 and 18 can leave the labyrinth 13 via the draincompartment 30.

[0023] In order that no coolant or lubricant can get into the passages19 and 20 from outside, a spray shield 21 is provided in the annularseal part 29 at the passages 19 and 20 and extends in the draincompartment 30 over the passages 19 and 20.

[0024] Should coolant and lubricant remnants stay on the end of theinner leg 15 of the C-section ring 7, they will be deflected by theextension 10. The droplets sticking to the extension 10 flow on an innersurface of the extension 10 into the catchment groove 18. Furthercoolant and lubricant drops can sit on the outer region of the inner leg15 where the taper of the inner leg 15 and centrifugal forces move themonce again to the outer end of the inner leg 15 and from there into thecatchment groove 18.

[0025] An annular add-on piece 22 is screwed to the outer end of theextension 10, substantially restricts the labyrinth 13, and also servesto press seal elements 23 and 24 against an abutment 25 and thus secureseal rings on the extension 10. The seal rings 23 and 24 are C-sectionglands that are prestressed by respective springs 26 and 27 against thebearing extension 4. The extension is formed with an inlet/outletpassage 28 that opens between the seals 23 and 24 so as to feed oil tolubricate the seal lips of the seal 23 or carry off excess oil from theseal region into an oil sump 29.

Reference Numeral List

[0026]1 Roll

[0027]2 Roll stub

[0028]3 Bearing sleeve

[0029]4 Bearing-sleeve extension

[0030]5 Support part

[0031]6 Bearing sleeve

[0032]7 C-section ring

[0033]8 Screws

[0034]9 Annular seal part

[0035]10 Extension

[0036]11 Outer leg

[0037]12 Wedge-shaped diverter

[0038]13 Labyrinth

[0039]14 Gap

[0040]15 Inner leg

[0041]16 Groove

[0042]17 Catchment groove

[0043]18 Catchment groove

[0044]19 Passage

[0045]20 Passage

[0046]21 Spray shield

[0047]22 Add-on part

[0048]23 Seal

[0049]24 Seal

[0050]25 Abutment

[0051]26 Spring

[0052]27 Spring

[0053]28 Inlet/outlet passage

[0054]29 Oil sump

[0055]30 Drain compartment

1. A seal assembly for a roll bearing wherein an annular element fixed rotationally to the roll stub (2) forms an annular seal face for an elastic stationary seal element (23, 24), a labyrinth seal (13) formed of stationary parts and parts on the roll (1) being formed between the seal element (23, 24) and the roll body, characterized in that the labyrinth (13) is formed by a C-section ring (7) fixed on an end of the roll (1) and forming a C-shaped cavity receiving a stationary annular cover part (9), the annular cover part (9) forms an outwardly open external drain compartment (30), the labyrinth gap (14) is remote from a floor of the drain compartment (30), and the annular cover part (9) has an extension (10) whose outer side forms part of the labyrinth path and whose inside carries the stationary seal elements (23, 24).
 2. The seal assembly according to claim 1, characterized in that the C-section ring (7) has a wedge-shaped diverter (12) directed at the roll surface.
 3. The seal assembly according to claim 1 or 2, characterized in that the annular cover part (9) has at least one internal and inwardly open catchment groove (17, 18) and the catchment groove (17, 18) has at its deepest location an outlet passage (19, 20) leading to the drain compartment (30) of the annular cover part (9).
 4. The seal assembly according to claim 3, characterized in that two catchment grooves (17, 18) are provided adjacent each other.
 5. The seal assembly according to claim 3 or 4, characterized in that a spray shield (21) is provided near the passages (19, 20) on an outer face of the annular cover part (9).
 6. The seal assembly according to one of claims 1 to 5, characterized in that the inner leg (15) of the C-section ring (7) has on its face turned toward the annular cover part (9) a groove (16) facing the catchment groove (17, 18) of the annular cover part (9) and the inner leg (15) of the C-section ring (7) is beveled on its end close to the projection (10) so that the inner leg (15) tapers toward its free end.
 7. The seal assembly according to one of claims 1 to 6, characterized in that the extension (10) has at its end an add-on part (22) restricting the labyrinth (13).
 8. The seal assembly according to claim 7, characterized in that the seal element (23, 24) is fixed between the add-on part (22) and an abutment (25) on the extension (10).
 9. The seal assembly according to one of claims 1 to 8, characterized in that the seal element (23, 24) is at least one gland whose seal lip has at least one annular spring (26, 27) that presses the seal lip against a seal surface of the annular extension (bearing-sleeve extension 4).
 10. The seal assembly according to claim 9, characterized in that the seal element (23, 24) is two glands next to each other and an input/output passage (28) is provided between the glands.
 11. The seal assembly according to claim 9, characterized in that the input/output passage (28) is shaped such that only a small amount of lubricant can move through into a space between the two seals (23, 24) sufficient to lubricate the lips of the seal element (23) and that the input/output passage (28) can carry off excess oil. 